Rear flasher etiquette

What's your opinion on group rides with rear flashers? I try to turn mine on when I'm at the back for extra traffic safety, but I inevitably drift up at some point so my flasher is then in the face of whoever is behind. Annoying or no big deal? I'm not bothered by the rear flashers ahead of me, but then again, I haven't come across any quite as bright as mine. I do have it angled down fairly low, so you'd have to be pretty far behind to be in the full-bright line of fire.

In other news, I'm very happy with my Bontrager Flare R, the 65 lumen daytime visibility mode adds some security to riding on roads where the traffic isn't expecting or used to bicycle traffic.